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From: Jose Ignacio Tornos Martinez <jtornosm@redhat.com>
To: oneukum@suse.com
Cc: davem@davemloft.net, edumazet@google.com, greg@kroah.com,
	jtornosm@redhat.com, kuba@kernel.org,
	linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
	netdev@vger.kernel.org, pabeni@redhat.com,
	stable@vger.kernel.org, stern@rowland.harvard.edu
Subject: Re: [PATCH v3] net: usb: ax88179_178a: avoid failed operations when device is disconnected
Date: Mon,  4 Dec 2023 12:31:18 +0100	[thread overview]
Message-ID: <20231204113119.11247-1-jtornosm@redhat.com> (raw)
In-Reply-To: <4ce32363-378c-4ea3-9a4e-d7274d4f7787@suse.com>

Hi Oliver,

> this is much better.
>> ...
> This is problematic. ndo_stop() is not limited to disconnection.
> It is also used whenever an interface transitions from up to down.
>> ...
>
> On a general note, you are going for a belt and suspenders approach.
> It seems to me that you have two options.
> 1. Do as Alan suggested and ignore ENODEV. You'd be acknowledging that
> these devices are hotpluggable and therefore -ENODEV is not an error
> 2. Use only a flag. But if you do that, you are setting it in the wrong
> place. It should be set in usbnet_disconnect()
Thank you for you help, I will do what you say.
I would like to try 2 first so that it only affects the unbind operation.
If I find any problem, I will try 1.

> O and, well, this is a very mior issue, but you've introduced a memory
> ordering issue. You ought to use smp_wmb() after setting the flag and
> smp_rmb() before reading it.
Thank you again, I'll keep that in mind

Best regards
José Ignacio


  reply	other threads:[~2023-12-04 11:31 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-29 15:16 [PATCH] net: usb: ax88179_178a: avoid failed operations when device is disconnected Jose Ignacio Tornos Martinez
2023-11-29 15:33 ` Oliver Neukum
2023-11-29 15:40   ` Alan Stern
2023-11-30  8:41     ` Jose Ignacio Tornos Martinez
2023-11-30 15:50       ` Alan Stern
2023-11-30 17:25         ` Jose Ignacio Tornos Martinez
2023-11-30 18:13           ` Alan Stern
2023-12-01 10:46             ` Jose Ignacio Tornos Martinez
2023-12-01 11:51             ` [PATCH v2] " Jose Ignacio Tornos Martinez
2023-12-01 12:25               ` Greg KH
2023-12-01 13:26                 ` [PATCH v3] " Jose Ignacio Tornos Martinez
2023-12-01 16:13                   ` Alan Stern
2023-12-01 17:27                     ` Jose Ignacio Tornos Martinez
2023-12-01 20:14                   ` Oliver Neukum
2023-12-04 11:31                     ` Jose Ignacio Tornos Martinez [this message]
2023-12-05 13:51                     ` [PATCH v4] " Jose Ignacio Tornos Martinez
2023-12-05 18:07                       ` Alan Stern
2023-12-06 12:17                         ` Jose Ignacio Tornos Martinez
2023-12-07 11:42                         ` [PATCH v5] " Jose Ignacio Tornos Martinez
2023-12-07 16:41                           ` Alan Stern
2023-12-07 17:50                             ` [PATCH v6] " Jose Ignacio Tornos Martinez
2023-12-07 20:23                               ` Alan Stern
2023-12-07 20:32                                 ` Jakub Kicinski
2023-12-08  4:56                                   ` Greg KH

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